Claims
- 1. A planar inductor, comprising:a planar inductance element comprising a plurality of windings, the plurality of windings all extending in the same plane; and at least one ferromagnetic layer stacked on said planar inductance element; wherein said at least one ferromagnetic layer comprises a plurality of ferromagnetic sub-layers which are stacked upon one another and form said ferromagnetic layer and have no electrically conductive material between them; and wherein an effective permeability μ 10 k at a frequency of 10 kHz of said at least one ferromagnetic layer is not less than 1×104.
- 2. The planar inductor according to claim 1, wherein a saturation magnetization 4πMζ of said at least one ferromagnetic layer is not less than 10 kG.
- 3. The planar inductor according to claim 1, wherein the thickness of each of said plurality of sub-layers is between 4 and 100 microns.
- 4. The planar inductor according to claim 1, wherein insulating layers and ferromagnetic layers stack on both surfaces of said planar inductance element.
- 5. The planar inductor according to claim 4, wherein said planar inductance element comprises a spiral coil.
- 6. The planar inductor according to claim 4, wherein said planar inductance element has a structure obtained by stacking a plurality of spiral coils with insulating layers interposed therebetween.
- 7. The planar inductor according to claim 1, further comprising:a coating of a mold resin surrounding said planar inductor element and said at least one ferromagnetic layer; and a relaxation layer formed on said ferromagnetic layer, for providing strain relaxation due to contraction of said coating of a mold resin when said coating of a mold resin is hardened.
- 8. The planar inductor according to claim 7, wherein said relaxation layer consists of an organic polymer film, said organic polymer film having a thermal deformation temperature which is higher than a hardening temperature of the mold resin.
- 9. The planar inductor according to claim 8, wherein said organic polymer film consists of polyphenylenesulfide.
- 10. The planar inductor according to claim 8, wherein the thickness of said organic polymer film is less than 20 microns.
- 11. A planar inductor having an inductance, comprising:at least one ferromagnetic layer, each ferromagnetic layer having a saturation magnetization that is greater than 10 kG and a thickness of less than 100 microns; and a coil stacked on said ferromagnetic layer and having a plurality of windings, the plurality of windings all extending in the same plane, wherein an effective permeability at a frequency of 10 kHz of said at least one ferromagnetic layer is not less than 1×104.
- 12. The planar inductor according to claim 11, further comprising:an insulating layer interposed between said coil and said ferromagnetic layer.
- 13. The planar inductor according to claim 11, wherein said saturation magnetization is greater than 12 kilogauss.
- 14. The planar inductor according to claim 11, wherein said coil comprises a plurality of stacked spiral coils, in which an insulating layer is disposed between each pair of adjacent coils.
- 15. The planar inductor according to claim 11, wherein said at least one ferromagnetic layer comprises a plurality of ferromagnetic layers.
- 16. A planar inductor, comprising:a laminated structure including a spiral conductor coil for conducting a current, said spiral conductor coil comprises a plurality of windings, the plurality of windings all extending in the same plane, wherein said spiral conductor coil is sandwiched between ferromagnetic layer, each of said ferromagnetic layers comprising a plurality of ferromagnetic ribbons which are sandwiched together; and wherein an effective permeability at 10 kilohertz of each ferromagnetic layer is at least 1×104.
- 17. A planar inductor comprising a laminated structure including a planar inductance element comprising a plurality of windings, the plurality of windings all extending in the same plane, said planar inductance element is sandwiched between ferromagnetic layers each including a plurality of ferromagnetic ribbons, each one of said plurality of ferromagnetic ribbons having a thickness of 100 microns or less,wherein an effective permeability at a frequency of 10 kHz of said at least one ferromagnetic layer is not less than 1×104.
- 18. The planar inductor according to claim 17, further comprising:insulating layers interposed between the planar inductance element and said ferromagnetic layers.
- 19. The planar inductor according to claim 17, wherein the thickness of each ferromagnetic ribbon is in the range between 4 and 100 microns.
- 20. The planar inductor according to claim 17, wherein each ferromagnetic layer has a thickness and a side length, and a ratio of the thickness to the side length of each ferromagnetic layer, composed of a plurality of ferromagnetic ribbons, falls within the range between 2×10−4 and 1×10−2.
- 21. A planar inductor, comprising:a planar inductance element comprising a plurality of conducting coils which are stacked upon one another and separated from one another only by an insulating non-ferromagnetic layer, each of said conducting coils comprising a plurality of windings, a first plurality of windings for a first one of the plurality of conducting coils all extending in the same plane; and at least one ferromagnetic layer stacked on said planar inductance element; wherein said at lest one ferromagnetic layer is formed from a plurality of ferromagnetic sub-layers that are stacked upon one another and each of the plurality of ferromagnetic sub-layers has a thickness of 100 microns or less, and wherein an effective permeability at a frequency of 10 kHz of said at least one ferromagnetic layer is not less than 1×104.
- 22. The planar inductor according to claim 21, wherein a saturation magnetization of said at least one ferromagnetic layer is not less than 10 kG.
- 23. The planar inductor according to claim 21, wherein a thickness of each of said plurality of sub-layers is between 4 and 100 microns.
- 24. A planar inductor comprising a laminated structure including spiral conductor coil sandwiched between ferromagnetic layers each including a plurality of ferromagnetic ribbons, each of said ferromagnetic ribbons having a thickness of 100 microns or less,wherein an effective permeability at a frequency of 10 kHz of said at least one ferromagnetic layer is not less than 1×104.
- 25. The inductor according to claim 24, wherein a saturation magnetization of each of said ferromagnetic layers is not less than 10 kilogauss.
- 26. The inductor according to claim 24, wherein the thickness of each of said plurality of ferromagnetic ribbons is between 4 and 100 microns.
- 27. The inductor according to claim 24, wherein said spiral conductor coil means comprises a plurality of coils with insulating layers interposed therebetween to form a stack of the plurality of coils and the insulating layers.
Priority Claims (3)
Number |
Date |
Country |
Kind |
63-246432 |
Sep 1988 |
JP |
|
63-246433 |
Sep 1988 |
JP |
|
1-14613 |
Jan 1989 |
JP |
|
Parent Case Info
This application is a continuation of application Ser. No. 08/059,350, filed May 11, 1993, U.S. Pat. No. 6,175,293 B1 which is a continuation of Ser. No. 08/414,455, filed Sep. 29, 1989, now abandoned which in turn claims priority to Japanese Application Nos. 3-246,432, filed Sep. 30, 1988; 63-246,433, filed Sep. 30, 1988, 63-246,433, filed Sep. 30, 1988, and 1-14,613, filed Jan. 24, 1989.
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Continuations (2)
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Number |
Date |
Country |
Parent |
08/059350 |
May 1993 |
US |
Child |
09/716403 |
|
US |
Parent |
08/414455 |
Sep 1989 |
US |
Child |
08/059350 |
|
US |